TỔNG QUAN VỀ CÁC VẤN ĐỀ mưa axit là thuật ngữ nói chung và bây giờ phổ biến liên quan đến mưa axit và tuyết axit. Bài viết này bàn về các khía cạnh vật lý và hóa học của hiện tượng mưa axit, trình bày kết quả từ một mạng lưới giám sát của Mỹ để minh họa cho thay đổi không gian và theo mùa, và thảo luận về xu hướng thời điểm mưa axit trong những thập kỷ gần đây. Một mô hình cân bằng hóa học được trình bày nhấn mạnh rằng người ta không thể. | A ACID RAIN OVERVIEW OF THE PROBLEM Acid rain is the general and now popular term that pertains to both acid rain and acid snow. This article discusses the physical and chemical aspects of the acid rain phenomenon presents results from a . monitoring network to illustrate spatial and seasonal variability and discusses time trends of acid rain during recent decades. A chemical equilibrium model is presented to emphasize that one cannot measure only pH and then expect to understand why a particular rain or melted snow sample is acidic or basic. Monitoring networks are now in operation to characterize the time trends and spatial patterns of acid rain. Definitions procedures and results from such measurement programs are discussed. The monitoring results are necessary to assess the effects of acid rain on the environment a topic only briefly discussed in this article. Chemicals in the form of gases liquids and solids are continuously deposited from the air to the plants soils lakes oceans and manmade materials on the earth s surface. Water H2O is the chemical compound deposited on the earth s surface in the greatest amount. The major atmospheric removal process for water consists of these steps 1 air that contains water vapor rises cools and condenses to produce liquid droplets . a visible cloud 2 in some clouds the water droplets are converted to the solid phase ice particles 3 within some clouds the tiny liquid droplets and ice particles are brought together to form particles that are heavy enough to fall out of the clouds as rain snow or a liquid-solid combination. When these particles reach the ground a precipitation event has occurred. As water vapor enters the base of clouds in an air updraft in step 1 above other solid liquid and gaseous chemicals are also entering the clouds. The chemicals that become incorporated into the cloud water liquid or ice are said to have been removed by in-cloud scavenging processes often called rainout. The chemicals that are
